Fig. 3

Abnormal vascularization in IVD. a Genes regulating abnormal alternative vascularization and other components of the interactome of hypoxia-inducible factor-1A (HIF1A) and high-temperature requirement A serine peptidase 1 (HTRA1) showed increased expression levels through degeneration grades (n = 26). Axes of x indicate state of degeneration, axes of y indicate average expression levels in log2. Results are based on VSN normalization. b Interactome of HIF1A and HTRA1 proposed by STRING database. c qRT-PCR validation of six selected genes regulating abnormal vascularization in degenerated grade II and III (n = 5), compared to severe degenerated grade IV and V (n = 5) AF tissues. Box plots represent relative mRNA expression normalized on GAPDH. The line across the box indicates the median, bubbles indicate outliers. Non-parametric Mann–Whitney–Wilcoxon U test for independent variables was used. Significance was showed as *p < 0.05